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x86, PAT: Remove duplicate memtype reserve in pci mmap

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pci mmap code was doing memtype reserve for a while now. Recently we
added memtype tracking in remap_pfn_range, and pci code indirectly calls
remap_pfn_range. So, we don't need seperate tracking in pci code
anymore. Which means a patch that removes ~50 lines of code :-).

Also, recently we found out that the pci tracking is not working as we expect
it to work in some cases. Specifically, userlevel X mmap of pci, with some
recent version of X, is having a problem with vm_page_prot getting reset.
The pci tracking uses vm_page_prot to pass on the protection type from parent
to child during fork.
a) Parent does a pci mmap
b) We look at PAT and get either UC_MINUS or WC mapping for parent
c) Store that mapping type in vma vm_page_prot for future use
d) This thread does a fork
e) Fork results in mmap_ops ->open for the child process
f) We get the vm_page_prot from vma and reserve that type for the child process

But, between c) and e) above, the vma vm_page_prot is getting reset to zero.
This results in PAT reserve failing at the time of fork as in here.
http://marc.info/?l=linux-kernel&m=123858163103240&w=2

This cleanup makes the above problem go away as we do not depend on
vm_page_prot in our PAT code anymore.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Suresh Siddha 2009-04-03 14:21:52 -07:00 committed by Linus Torvalds
parent 78609a812e
commit 5a3ae27605
1 changed files with 0 additions and 46 deletions
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46
arch/x86/pci/i386.c
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@ -258,24 +258,7 @@ void pcibios_set_master(struct pci_dev *dev)
pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
}
static void pci_unmap_page_range(struct vm_area_struct *vma)
{
u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
free_memtype(addr, addr + vma->vm_end - vma->vm_start);
}
static void pci_track_mmap_page_range(struct vm_area_struct *vma)
{
u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
unsigned long flags = pgprot_val(vma->vm_page_prot)
& _PAGE_CACHE_MASK;
reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL);
}
static struct vm_operations_struct pci_mmap_ops = {
.open = pci_track_mmap_page_range,
.close = pci_unmap_page_range,
.access = generic_access_phys,
};
@ -283,11 +266,6 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
enum pci_mmap_state mmap_state, int write_combine)
{
unsigned long prot;
u64 addr = vma->vm_pgoff << PAGE_SHIFT;
unsigned long len = vma->vm_end - vma->vm_start;
unsigned long flags;
unsigned long new_flags;
int retval;
/* I/O space cannot be accessed via normal processor loads and
* stores on this platform.
@ -308,30 +286,6 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
vma->vm_page_prot = __pgprot(prot);
flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK;
retval = reserve_memtype(addr, addr + len, flags, &new_flags);
if (retval)
return retval;
if (flags != new_flags) {
if (!is_new_memtype_allowed(flags, new_flags)) {
free_memtype(addr, addr+len);
return -EINVAL;
}
flags = new_flags;
vma->vm_page_prot = __pgprot(
(pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK) |
flags);
}
if (((vma->vm_pgoff < max_low_pfn_mapped) ||
(vma->vm_pgoff >= (1UL<<(32 - PAGE_SHIFT)) &&
vma->vm_pgoff < max_pfn_mapped)) &&
ioremap_change_attr((unsigned long)__va(addr), len, flags)) {
free_memtype(addr, addr + len);
return -EINVAL;
}
if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start,
vma->vm_page_prot))